1. Field of the Invention
The invention is related to the field of communications, and in particular, to allow a mobile device that is subject to a communication restriction to respond to a priority call.
2. Statement of the Problem
Wireless networks have integrated methods of issuing communication restrictions to control the network flow during special circumstances, such as a network malfunction, overload, or at other times when the performance of the network is jeopardized. A communication restriction when applied to a mobile device of a wireless network restricts its ability to initiate or respond to network communications to connect a call. One example of a communication restriction is the access class barring technique used by Universal Mobile Telecommunication System (UMTS), Global System for Mobile Communications (GSM), and other compatible communication service providers. The 3rd Generation Partnership Project (3GPP) Technical Specification Group Services and System Aspects; Service accessibility (Release 7) document discusses this in Chapter 4, Access Control (3GPP TS 22.011 V7.1.0, found at www.3gpp.org). The specification allocates a set of access classes and requires that a GSM compatible mobile device be a member of at least one access class. A mobile device is under a communication restriction/access class bar when the mobile device receives an access control restriction broadcast by the wireless network which contains the access class for the mobile device. While the GSM compatible mobile device is subject to an access class bar the mobile device will continue to receive and monitor paging requests from the wireless network. However, the mobile device is prohibited from responding to a paging request and cannot make or receive a call. The wireless network will continue to monitor the network traffic and as the situation improves the wireless network will take steps to remove the communication restrictions.
The special circumstances resulting in the use of a communication restriction are varied. A malfunction caused by component failure, physical damage to the network, or other electro-mechanical failure may result in a need to restrict network traffic. An overload can be caused by something as simple as a shopping mall around the holiday season or as complex as an emergency situation, but in any case is caused by a large number of users in a particular area concurrently attempting to place phone calls. Whether malfunction or overload, users are subject to a communication restriction and cannot make or receive calls.
At the same time the need to provide individuals and organizations who respond to man-made and natural disasters with priority communication has long been recognized. Priority services are made available to authorized government, emergency and other key personnel so that in times of network congestion priority calls can be placed. Priority calls receive specialized processing from the wireless network to assure that each priority call is connected over the next available channel. By doing so both the expediency and probability of establishing a connection with crucial personnel is much improved. One example of a priority service is Wireless Priority Services (WPS). WPS is an enhancement to wireless communication services that provides for National Security and Emergency Preparedness (NS/EP) calls. Another example is Government Emergency Telecommunications System (GETS). GETS is for primarily handling landline initiated priority calls. WPS and GETS are complementary to each other and both use the same NS/EP protocol to initiate a priority call. WPS and GETS are discussed as just two examples of priority services.
Thus, a potential conflict may occur between communication restrictions and priority services. As an example, a wireless network may be congested as users close to an emergency initiate calls, thereby causing the network to invoke communication restrictions. But at the same time authorized personnel (i.e., priority service users) may be attempting to contact a public service user who may be close to the same incident by using a priority service. This situation would cause the mobile device being used by the public service user to restrict communication such that the public service user could not respond to the priority call in a timely manner.